* Add signature to blob
* Change Signable trait to support returning references to signable data
* Add signing to broadcast
* Verify signatures in window_service
* Add testing for signatures to erasure
* Add RPC for getting current slot, consume RPC call in test_repairman_catchup for more deterministic results
* Restart node test (#3459)
* Add test to local_cluster for restarting a node
* fix so that we don't hit end of epoch - leader not found before trying to transfer
* Do not look for confirmations, b/c nobody is voting on empty transmissions in this single node test